Ontological Modeling: Part 11 Some Differences between Owl Ontologies and Typical Databases

This is the eleventh in a series of articles on ontology-based approaches to modeling. The main focus is on popular ontology languages proposed for the Semantic Web, such as the Resource Description Framework (RDF), RDF Schema (RDFS), and the Web Ontology Language (OWL). OWL is based on description logic. A later series of articles will explore other logic-based languages such as datalog. The first article [2] introduced ontologies and the Semantic Web, and covered basic concepts in the Resource Description Framework (RDF), contrasting them with other data modeling approaches. The second article [3] discussed the N3 notation for RDF, and covered the basics of RDF Schema. The third article [4] provided further coverage of RDFS, and introduced different flavors of the Web Ontology language (OWL). The fourth article [5] discussed basic features of OWL, mainly using Manchester syntax. The fifth article [6] discussed OWL taxonomy, comparison operators for classes, data types and predicates, and examined inverses, functional roles and keys in more depth. The sixth article [7] covered cardinality restrictions in OWL 2. The seventh article [8] discussed the union, intersection, and complement operators in OWL 2. The eighth article [9] explored support for ring constraints within OWL 2. The ninth article [10] discussed enumerated types as well as value restrictions on properties in OWL 2. The tenth article [11] examined OWL 2’s support for property chains, and compared this with related concepts in data modeling approaches. The current article discusses the logical status of structural statements in OWL 2, contrasting this with other data modeling approaches that support both integrity constraints and derivation rules.